Back brace



FIG. 1 is an embodiment of a top right, front perspective view of a back brace showing our new design;

FIG. 2 is front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a front, top plan view thereof; and,

FIG. 7 is a rear, bottom plan view thereof.

The features shown in broken lines with consistent dash lengths illustrate ornamentation, features, and/or environment that form no part of the claimed design. 

CLAIM The ornamental design for a back brace, as shown and described. 